A system and method for catalytic reduction of carbon dioxide by hydrogenation in an arc-shaped thin plate

Abstract

The present disclosure relates to a system and method for catalytic reduction hydrogenation of arc-shaped thin-plate carbon dioxide, which forms a feeding chamber and a discharging chamber between the top and bottom of the temperature adjusting layer and the shell, and forms a reaction chamber in the internal cavity of the temperature adjusting layer, and makes the reaction chamber communicate with the feeding chamber and the discharging chamber through multiple through holes, so that the hydrogenation reaction material can enter the reaction chamber for reaction after buffering in the feeding chamber, the residence time of the hydrogenation reaction material in the photocatalyst reactor is prolonged, and the hydrogenation reaction effect of carbon dioxide is improved. Furthermore, multiple catalyst arc-shaped thin-plates with photocatalysts attached to the side surfaces are arranged in the reaction chamber, which can improve the specific surface area of the catalyst and further improve the hydrogenation reaction effect of carbon dioxide.

Description

Technical Field

[0001] This disclosure relates to the field of carbon dioxide capture, and more specifically, to a system and method for an arc-shaped thin-plate catalytic reduction hydrogenation reaction of carbon dioxide. Background Technology

[0002] Currently, due to the massive emission of carbon dioxide, the greenhouse effect is intensifying, severely impacting the global climate. Therefore, effectively reducing carbon dioxide concentration has become a key research focus. In existing technologies, photocatalytic reduction is commonly used to convert carbon dioxide and hydrogen into fuel compounds such as alkanes, alkenes, and alcohols. The collected carbon dioxide and green hydrogen are used; the photocatalyst is typically a semiconductor material, excited by light, and the electrons and holes generated by the photocatalyst participate in the carbon dioxide hydrogenation reaction.

[0003] The prior art CN206730862U discloses a photocatalytic reduction carbon dioxide reactor. The spiral reaction tube of this reactor is the main body for the reaction of carbon dioxide and hydrogen, and a photocatalyst is attached to the inner wall of the spiral reaction tube, which can convert carbon dioxide and hydrogen into energy compounds. However, the reactor and the hydrogenation reactants only flow in the region of the spiral reaction tube, the reaction channel is single, the total surface area of ​​the reactants in contact with the catalyst is small, and the light energy generated by the light source cannot be fully utilized, resulting in a large amount of light energy consumption. Therefore, the efficiency and quality of the photocatalytic reduction carbon dioxide reactor are not high. Summary of the Invention

[0004] The purpose of this disclosure is to provide a system and method for catalytic reduction and hydrogenation of carbon dioxide using an arc-shaped thin plate, in order to solve the problems of single reaction pathway, low light utilization, small total surface area of ​​reactants in contact with catalyst, and inflexible reaction conditions in the prior art.

[0005] To achieve the above objectives, the first aspect of this disclosure provides a system for an arc-shaped thin-plate carbon dioxide catalytic reduction hydrogenation reaction. This system includes a gas mixer, a photocatalytic reactor, a blower, a liquid collector, and a gas collector. The photocatalytic reactor includes a shell with an overall cylindrical structure, a temperature regulating layer, a diffuse reflection layer, a catalyst-coated fiber optic assembly, and a tunable wavelength light source. The shell contains, from top to bottom, a feed chamber, a reaction chamber, and a discharge chamber. The temperature regulating layer covers the outside of the reaction chamber. The diffuse reflection layer, the catalyst arc-shaped thin-plate assembly, and the tunable wavelength light source are arranged sequentially from the outside to the inside of the reactor. The reaction chamber is internal; the feed chamber and the discharge chamber are respectively provided with a feed inlet and a discharge outlet; the feed inlet is connected to the outlet of the gas mixer, and the discharge outlet is connected to the inlet of the blower; the top and bottom surfaces of the reaction chamber are respectively provided with through holes, so that the feed chamber and the discharge chamber are connected to the reaction chamber through the through holes; the catalyst arc-shaped thin plate assembly includes multiple catalyst arc-shaped thin plates, and the sidewalls of the catalyst arc-shaped thin plates are attached with photocatalysts; the upper and lower ends of the catalyst arc-shaped thin plates extend to the feed chamber and the discharge chamber respectively, and the concave surface of the arc-shaped thin plates faces the axis of the shell.

[0006] Optionally, the diffuse reflection layer is disposed on the inner wall of the temperature regulating layer; the adjustable wavelength light source is disposed inside the reaction chamber along the axial direction of the housing, preferably coaxially disposed with the reaction chamber; the adjustable wavelength light source includes one or more of xenon lamp light source, QTH adjustable quartz halogen lamp light source, deuterium lamp light source and halogen tungsten lamp light source.

[0007] Optionally, the surface of the catalyst arc-shaped thin plate extends along the axial direction of the shell, the catalyst arc-shaped thin plate is an arc-shaped thin plate of equal thickness and equal width at the top and bottom; the arc α of the arc-shaped thin plate is 20 to 30 rad and the thickness is 1 to 10 mm; multiple catalyst arc-shaped thin plates are arranged in parallel, and multiple catalyst arc-shaped thin plates are arranged at intervals along the same circumference on a plane perpendicular to the axial direction.

[0008] Optionally, the ratio of the height of the reaction chamber to the height of the shell is (0.5 to 0.7):1; the diameter of the through hole is 5 to 10 mm.

[0009] Optionally, the system further includes a liquid collector gas phase outlet pipeline divided into a circulating gas phase pipeline and a gas phase collection pipeline; the liquid collector gas phase outlet is connected to the feed inlet of the photocatalytic reactor through the circulating gas phase pipeline; and the liquid collector gas phase outlet is connected to the gas collector inlet through the gas phase collection pipeline.

[0010] Optionally, the system further includes a control unit and a carbon dioxide concentration detector disposed at the feed inlet of the photocatalytic reactor; the control unit is electrically connected to the carbon dioxide concentration detector, the tunable wavelength light source and the temperature regulation layer, and is used to receive the carbon dioxide concentration signal from the carbon dioxide concentration detector and adjust the input power of the tunable wavelength light source and / or the temperature regulation layer according to the signal.

[0011] The second aspect of this disclosure is a method for performing a carbon dioxide catalytic reduction hydrogenation reaction using the system described in the first aspect. The method includes: mixing carbon dioxide and hydrogen in a gas mixer to obtain a hydrogenation reaction material; introducing the hydrogenation reaction material into the feed chamber of a photocatalytic reactor, and through a through-hole on the top surface of the reaction chamber, where it contacts the catalyst on a catalyst arc-shaped thin plate under light irradiation conditions to perform a hydrogenation reaction, obtaining a hydrogenation reaction product; introducing the hydrogenation reaction product into a discharge chamber through a through-hole on the bottom surface of the reaction chamber; and introducing the hydrogenation reaction product in the discharge chamber sequentially into a gas collector via a blower and a liquid collector.

[0012] Optionally, the method further includes increasing the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction when the carbon dioxide concentration in the hydrogenation reactants is less than a first threshold; the first threshold being 28-33% by volume; and decreasing the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction when the carbon dioxide concentration in the hydrogenation reactants is greater than a second threshold; the second threshold being 20-25% by volume.

[0013] Optionally, the method further includes: allowing the hydrogenation reaction product to enter a liquid collector for gas-liquid separation under the action of the blower, obtaining a liquid phase product and a separated gas phase; when the carbon dioxide concentration in the separated gas phase is less than a collection threshold, allowing the separated gas phase to enter the gas collector; when the carbon dioxide concentration in the separated gas phase is greater than the collection threshold, allowing the separated gas phase to return to the photocatalytic reactor for further reaction, until the carbon dioxide content in the separated gas phase is less than the collection threshold, allowing the separated gas phase to enter the gas collector; the collection threshold is 10-30% by volume.

[0014] Optionally, the photocatalyst includes one or more of titanium dioxide, zinc oxide, or tin oxide; the conditions for the hydrogenation reaction include: a reaction temperature of 50–100°C, a reactant residence time of 5–10 s, and a light irradiance of 20–200 W / m² from the tunable wavelength light source. 2 .

[0015] Through the above technical solution, a feeding chamber is formed between the temperature regulating layer and the top of the shell, a discharging chamber is formed between the temperature regulating layer and the bottom of the shell, and a reaction chamber is formed within the internal cavity of the temperature regulating layer. Furthermore, the reaction chamber is connected to the feeding and discharging chambers through multiple through-holes, allowing the hydrogenation reactants to enter the reaction chamber through the through-holes after being buffered in the feeding chamber, where they come into contact with the photocatalyst for hydrogenation. The hydrogenation reactants diffuse throughout the entire reaction chamber after entering, increasing their residence time in the photocatalyst reactor and thus improving the hydrogenation effect of carbon dioxide. Moreover, multiple arc-shaped catalyst plates with photocatalysts attached to their sidewalls are arranged in the reaction chamber, allowing the hydrogenation reactants to react on the sidewalls of these plates, increasing the total surface area of ​​contact between the hydrogenation reactants and the catalyst, thereby improving the efficiency and effect of the carbon dioxide hydrogenation reaction. Additionally, a diffuse reflection layer is provided in the photocatalyst reactor, allowing light to be continuously reflected within a relatively small enclosed space, significantly improving light utilization and correspondingly enhancing the efficiency and effect of the photocatalytic reaction.

[0016] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0018] Figure 1 This is a schematic diagram of a cross-section of a photocatalytic reactor disclosed herein.

[0019] Figure 2 This is a top view of another photocatalytic reactor disclosed herein.

[0020] Figure 3 This is a schematic diagram of an arc-shaped thin plate of catalyst used in a photocatalytic reactor disclosed herein.

[0021] Figure 4 This is a schematic diagram of a system for catalytic reduction and hydrogenation of carbon dioxide using an arc-shaped thin plate.

[0022] Figure 5 This is a schematic diagram of the photocatalytic reactor used in Comparative Example 1 of this disclosure.

[0023] Explanation of reference numerals in the attached figures

[0024] 1 Gas mixer; 2 Photocatalytic reactor; 3 Fan; 4 Liquid collector; 5 Gas collector; 6 First valve; 7 Second valve; 8 Third valve; 9 Control unit; 20 Housing; 21 Temperature regulating layer; 22 Diffuse reflection layer; 23 Catalyst arc-shaped thin plate; 24 Adjustable wavelength light source; 25 Feed chamber; 26 Discharge chamber; 27 Through hole; 29 Heating layer; 30 Reflective layer; 31 Reaction tube; 32 Light source. Detailed Implementation

[0025] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0026] In this disclosure, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its normal operating state, for example, as shown in the reference. Figure 1 In the drawing orientation, "inner" and "outer" refer to those relative to the outline of the device. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] like Figure 1 and Figure 4 As shown, the first aspect of this disclosure provides a system for a curved thin-plate carbon dioxide catalytic reduction hydrogenation reaction. The system includes a gas mixer 1, a photocatalytic reactor 2, a blower 3, a liquid collector 4, and a gas collector 5. The photocatalytic reactor 2 includes a cylindrical shell 20, a temperature regulating layer 21, a diffuse reflection layer 22, a catalyst-coated optical fiber assembly, and a tunable wavelength light source 24. The shell 20 contains, from top to bottom, a feed chamber 25, a reaction chamber, and a discharge chamber 26. The temperature regulating layer 21 covers the outside of the reaction chamber. The diffuse reflection layer 22, the curved thin-plate catalyst assembly, and the tunable wavelength light source 24 are arranged sequentially from the outside to the inside of the reaction chamber. The interior of the chamber includes a feed chamber 25 and a discharge chamber 26, each with a feed inlet and a discharge outlet. The feed inlet is connected to the outlet of the gas mixer 1, and the discharge outlet is connected to the inlet of the blower 3. The top and bottom surfaces of the reaction chamber are provided with through holes 27, allowing the feed chamber 25 and the discharge chamber 26 to communicate with the reaction chamber through the through holes 27. The catalyst arc-shaped thin plate assembly includes multiple catalyst arc-shaped thin plates 23, with photocatalysts attached to the sidewalls of the catalyst arc-shaped thin plates 23. The upper and lower ends of the catalyst arc-shaped thin plates 23 extend to the feed chamber 25 and the discharge chamber 26, respectively, with the concave surface of the arc-shaped thin plates facing the axis of the housing 20.

[0028] Through the above technical solution, a feeding chamber is formed between the temperature regulating layer and the top of the shell, a discharging chamber is formed between the temperature regulating layer and the bottom of the shell, and a reaction chamber is formed within the internal cavity of the temperature regulating layer. Furthermore, the reaction chamber is connected to the feeding and discharging chambers through multiple through-holes, allowing the hydrogenation reactants to enter the reaction chamber through the through-holes after being buffered in the feeding chamber, where they come into contact with the photocatalyst for hydrogenation. The hydrogenation reactants diffuse throughout the entire reaction chamber after entering, increasing their residence time in the photocatalyst reactor and thus improving the hydrogenation effect of carbon dioxide. Moreover, multiple arc-shaped catalyst plates with photocatalysts attached to their sidewalls are arranged in the reaction chamber, allowing the hydrogenation reactants to react on the sidewalls of these plates, increasing the total surface area of ​​contact between the hydrogenation reactants and the catalyst, thereby improving the efficiency and effect of the carbon dioxide hydrogenation reaction. Additionally, a diffuse reflection layer is provided in the photocatalyst reactor, allowing light to be continuously reflected within a relatively small enclosed space, significantly improving light utilization and correspondingly enhancing the efficiency and effect of the photocatalytic reaction.

[0029] The gas mixer used in this disclosure is a conventional choice in the art, and this application does not make any special requirements. For example, the gas mixer is generally cylindrical, with a hydrogen inlet and a carbon dioxide inlet on the top surface of the cylindrical body, and a mixed raw material gas outlet on the bottom surface of the cylindrical body; and multiple baffles are staggered inside the cylindrical body to make the hydrogen and carbon dioxide mix evenly under the action of the baffles.

[0030] The fan used in this disclosure is a conventional choice in the art, and this application does not make any special requirements, as long as it can transport the hydrogenation reaction products in the photocatalytic reactor to the liquid collector 4.

[0031] The liquid collector 4 and gas collector used in this disclosure are conventional choices in the art, and this application does not make any special requirements. For example, the liquid collector 4 can be selected from a gas-liquid separation tower and / or a gas-liquid separation tank. In this embodiment, the liquid collector 4 includes a hydrogenation reaction product inlet, a liquid phase product outlet, and a separated gas phase outlet. The hydrogenation reaction product inlet of the liquid collector 4 is connected to the outlet of the blower so that the hydrogenation reaction product can enter the liquid collector 4; the liquid phase product outlet of the liquid collector 4 is used to connect to a liquid phase product using device; the separated gas phase outlet of the liquid collector 4 is connected to the inlet of the gas collector so that the separated gas phase can be collected by the gas collector.

[0032] like Figure 1 and Figure 2As shown, the temperature regulating layer 21 in the photocatalytic reactor 2 has an overall cylindrical structure, which is set inside the shell 20. The sidewall of the temperature regulating layer 21 is tightly connected to the inner wall of the shell 20, and the internal cavity of the temperature regulating layer 21 forms a reaction chamber. A gap is left between the top surface of the temperature regulating layer 21 and the top of the shell 20 to form a feed chamber 25, and a gap is left between the bottom surface of the temperature regulating layer 21 and the bottom of the shell 20 to form a discharge chamber 26.

[0033] In one embodiment, in order to further increase the residence time of the reactants in the reaction chamber, on the one hand, a plurality of through holes 27 are uniformly provided on the top and bottom surfaces of the reaction chamber, and the diameter of the through holes 27 is 5-10 mm, preferably 7-8 mm; on the other hand, the through holes 27 on the top surface of the reaction chamber and the through holes 27 on the bottom surface of the reaction chamber are staggered.

[0034] The through-hole 27 on the top surface of the reaction chamber is formed in the upper temperature regulating layer 21, and the through-hole 27 on the bottom surface of the reaction chamber is formed in the lower temperature regulating layer 21.

[0035] In one embodiment, the temperature regulating device used in the temperature regulating layer 21 is a conventional choice in the art, and this application does not make any requirements. For example, the temperature regulating device used in the temperature regulating layer 21 is an electric heater.

[0036] In one embodiment, the ratio of the height of the reaction chamber to the height of the shell 20 is (0.5-0.7):1, preferably (0.55-0.65):1.

[0037] In one embodiment, a diffuse reflection layer 22 is provided inside the internal cavity of the reaction chamber, and the diffuse reflection layer 22 is placed on the inner wall of the temperature regulating layer 21; the overall structure of the diffuse reflection layer 22 can be conventionally selected in the art, for example, the overall structure of the diffuse reflection layer 22 can be a square cylindrical structure, a circular cylindrical structure or an irregular cylindrical structure, preferably a circular cylindrical structure, and more preferably a circular cylindrical structure without a top surface and a bottom surface.

[0038] The diffuse reflection layer 22 and the inner wall of the temperature regulating layer 21 can be tightly bonded or have a certain gap. Preferably, the diffuse reflection layer 22 and the inner wall of the temperature regulating layer 21 are tightly bonded.

[0039] In one embodiment, the diffuse reflection layer 22 is a reflective grating layer, wherein the reflective grating layer contains 1000-1500 optical slits per millimeter of scribe line. The material of the reflective grating layer includes one or more environmentally friendly materials such as PET, PP, PVC, and TPU.

[0040] In one embodiment, the form of the tunable wavelength light source 24 is conventionally chosen in the art, and this application does not make any special requirements. For example, the light source used in this disclosure is in the form of a rod-shaped light source. The tunable wavelength light source 24 is disposed inside the reaction chamber along the axial direction of the housing 20. Preferably, the tunable wavelength light source 24 is coaxially disposed with the housing 20.

[0041] In one embodiment, the tunable wavelength light source 24 can be selected from the TLS series tunable wavelength light source or the CP-L series wavelength-tunable monochromatic light source; preferably, the tunable wavelength light source 24 includes one or more of xenon lamp sources, QTH tunable quartz halogen lamp sources, deuterium lamp sources, and halogen tungsten lamp sources. In this embodiment, the wavelength of the tunable wavelength light source 24 is 200nm-2500nm.

[0042] In one embodiment, the temperature regulating layer 21 and the tunable wavelength light source 24 are respectively provided with an electrical transmission device, so that the tunable wavelength light source 24 can adjust the light irradiance intensity according to the input power.

[0043] In one embodiment, the catalyst arc-shaped thin plate assembly includes a plurality of catalyst arc-shaped thin plates 23, which are uniformly disposed in the region between the inner side of the diffuse reflection layer 22 and the outer side of the tunable wavelength light source 24.

[0044] The catalyst arc-shaped thin plate 23 is arranged parallel to the tunable wavelength light source 24, that is, the surface of the catalyst arc-shaped thin plate 23 is arranged along the axial direction of the housing 20.

[0045] The catalyst arc-shaped thin plates 23 are arranged in parallel, and the catalyst arc-shaped thin plates 23 are arranged at intervals along the same circumference on a plane perpendicular to the axial direction. In addition, the catalyst arc-shaped thin plates 23 penetrate the reaction chamber.

[0046] In one implementation, such as Figure 3 As shown, the catalyst arc-shaped thin plate 23 is an arc-shaped thin plate of uniform thickness and equal width at both ends; the ratio of the height of the arc-shaped thin plate to the height of the shell 20 is (0.7-0.95):1, preferably (0.75-0.9):1; the thickness of the uniformly thick arc-shaped thin plate is 1-10 mm, preferably 5-10 mm, and more preferably 7-8 mm. The arc α of the uniformly thick arc-shaped thin plate is 20-30 rad, preferably 22-28 rad.

[0047] In one embodiment, the material of the arc-shaped thin plate can be selected from one or more of acrylic sheet, MDF, plywood and fine-mesh board. In order to further improve the light utilization rate, the material of the catalyst arc-shaped thin plate 23 can be set to a transparent arc-shaped thin plate. For example, the material of the arc-shaped thin plate can be a transparent acrylic sheet.

[0048] In one embodiment, a first valve 6 is also provided on the outlet pipeline of the gas mixer 1 to control whether the hydrogenation reaction material enters the photocatalytic reactor 2.

[0049] In one embodiment, the gas phase outlet pipeline of the liquid collector 4 is divided into a circulating gas phase pipeline and a gas phase collection pipeline; the gas phase outlet of the liquid collector is connected to the feed inlet of the photocatalytic reactor 2 through the circulating gas phase pipeline; the gas phase outlet of the liquid collector 4 is connected to the inlet of the gas collector 5 through the gas phase collection pipeline.

[0050] In one embodiment, a second valve 7 is provided on the gas phase collection pipeline, and a third valve 8 is provided on the circulating gas phase pipeline to control the return of the separated gas phase to the photocatalytic reactor 2 or into the gas collector 5.

[0051] In one embodiment, the system further includes a control unit 9, and a carbon dioxide concentration detector is provided at the gas phase product outlet of the liquid collector 4 for detecting the carbon dioxide concentration in the separated gas phase. The control unit 9 is electrically connected to the carbon dioxide concentration detector, the first valve 6, the second valve 7, and the third valve 8, respectively, for receiving signals from the carbon dioxide concentration detector and adjusting the opening and closing of the first valve 6, the second valve 7, and the third valve 8 according to the signals.

[0052] In this embodiment, the system's operating state can be divided into a first operating state and a second operating state through the adjustment method of the control unit. In the first operating state, the control unit keeps the first valve 6 and the second valve 7 open, and the third valve 8 closed, so that the mixture of hydrogen and carbon dioxide sequentially passes through the photocatalytic reactor 2, the fan 3, and the liquid collector 4, resulting in the liquid phase exiting the system and the separated gas phase directly entering the gas collector 5. In the second operating state, the first valve 6 and the second valve 7 are kept closed, and the third valve 8 is kept open, so that the mixture of hydrogen and carbon dioxide circulates sequentially between the photocatalytic reactor 2, the fan 3, and the liquid collector 4.

[0053] In one embodiment, a carbon dioxide concentration detector is provided at the feed inlet of the photocatalytic reactor 2 to detect the concentration of carbon dioxide in the material entering the photocatalytic reactor 2; the control unit 9 is electrically connected to the carbon dioxide concentration detector, the tunable wavelength light source 24 and the temperature regulating layer 21, and is used to receive the carbon dioxide concentration signal from the carbon dioxide concentration detector and adjust the input power of the tunable wavelength light source 24 and / or the temperature regulating layer 21 according to the signal.

[0054] The second aspect of this disclosure uses the system described in the first aspect to perform a carbon dioxide catalytic reduction hydrogenation reaction. The method includes: mixing carbon dioxide and hydrogen in a gas mixer 1 to obtain a hydrogenation reaction material; introducing the hydrogenation reaction material into the feed chamber 25 of a photocatalytic reactor 2, and through a through-hole 27 on the top surface of the reaction chamber, where it contacts the catalyst on a catalyst arc-shaped thin plate 23 under light irradiation to perform a hydrogenation reaction, obtaining a hydrogenation reaction product; introducing the hydrogenation reaction product into a discharge chamber 26 through the through-hole 27 on the bottom surface of the reaction chamber; and introducing the hydrogenation reaction product in the discharge chamber 26 sequentially into a gas collector 5 via a blower 3 and a liquid collector 4.

[0055] Through the above technical solution, the hydrogenation reactants are brought into contact with the catalyst on the arc-shaped thin plate in the reaction chamber of the photocatalytic reactor 2 for hydrogenation reaction. The resulting hydrogenation reaction products are separated by the liquid collector 4, with the liquid phase exiting the system and the separated gas phase being collected. This photocatalytic reactor 2 not only increases the specific surface area of ​​the catalyst but also extends the residence time of the hydrogenation reactants in the reactor, thereby improving the hydrogenation effect of carbon dioxide. Furthermore, the diffuse reflection layer in the photocatalytic reactor allows light to be continuously reflected within a relatively small enclosed space, significantly improving light utilization and consequently enhancing the efficiency and effectiveness of the photocatalytic reaction.

[0056] In one embodiment, the conditions for the hydrogenation reaction include: a reaction temperature of 50–100°C, preferably 60–80°C; a reactant residence time of 5–10 s, preferably 7–8 s; and a light irradiance of 20–200 W / m² from the tunable wavelength light source 24. 2 Preferably, it is 50-150W / m 2 .

[0057] In one embodiment, the hydrogen can be obtained through water electrolysis powered by renewable energy sources such as solar, wind, and biomass energy, wherein the concentration of the hydrogen is 90% by volume or higher. The carbon dioxide can be obtained from one or more of the following: burning fossil fuels, industrial production, agricultural activities, and energy consumption, wherein the concentration of the carbon dioxide is 90% by volume or higher.

[0058] In this embodiment, since the hydrogen raw material is generated by water electrolysis, and the electricity generated by the aforementioned renewable energy source is unstable, there will be fluctuations in the hydrogen concentration. Therefore, the ratio of carbon dioxide to hydrogen in the hydrogenation reaction material obtained by mixing in gas mixer 1 is unstable. By using the method disclosed herein, the reaction conditions of the hydrogenation reaction can be flexibly adjusted according to the above ratio, and the problem of product quality deterioration caused by fluctuations in the quality of raw materials can be avoided.

[0059] In one embodiment, the molar ratio of hydrogen and carbon dioxide entering the gas mixer 1 is (2-4):1, preferably (2.5-3.5):1.

[0060] In one embodiment, the photocatalyst comprises one or more of titanium dioxide particles, zinc oxide particles, and tin oxide particles, preferably titanium dioxide particles. Preferably, the average particle size of the photocatalyst is 10–50 nm, more preferably 20–40 nm.

[0061] In this embodiment, when light with energy greater than or equal to the band gap irradiates the photocatalyst nanoparticles, electrons in their valence band will be excited and jump to the conduction band, leaving relatively stable holes in the valence band, thereby forming electron-hole pairs, which cause the carbon dioxide reduction reaction to occur. Therefore, the hydrogenation reaction of carbon dioxide and hydrogen needs to be carried out in the presence of a photocatalyst.

[0062] In one embodiment, a carbon dioxide concentration detector at the inlet of the photocatalytic reactor detects the carbon dioxide concentration in the hydrogenation reaction products, and transmits the detection result to a control unit 9. The control unit compares the result with a first threshold and a second threshold: when the carbon dioxide concentration in the hydrogenation reaction material is less than the first threshold, the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction are increased; the first threshold is 28–33% by volume, preferably 30–31% by volume; when the carbon dioxide concentration in the hydrogenation reaction material is greater than the second threshold, the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction are decreased; the second threshold is 20–25% by volume, preferably 22–23% by volume.

[0063] In this embodiment, the hydrogenation reaction rate increases with increasing reaction temperature because the activation energy decreases, molecular motion speed increases, and the collision frequency between reactant molecules increases. However, the reaction rate slows down when the temperature exceeds a critical point because the photocatalyst deactivates at high temperatures. Therefore, the heating layer is improved to allow for temperature regulation, and the optimal reaction temperature must be selected based on different catalysts to maximize reaction efficiency. Only light absorbed by the reaction system can trigger the photochemical reaction, and the system exhibits selective light absorption with a suitable wavelength. The ability to flexibly adjust the reaction temperature and / or light irradiation intensity of the hydrogenation reaction based on the carbon dioxide concentration in the hydrogenation products ensures that the hydrogenation reaction always proceeds under favorable conditions, thereby further enhancing the effectiveness of carbon dioxide hydrogenation.

[0064] In one embodiment, the method further includes: allowing the hydrogenation reaction product to enter a liquid collector 4 under the action of the blower 3 for gas-liquid separation to obtain a liquid product and a separated gas phase; allowing the liquid product to exit the system; allowing a carbon dioxide concentration detector to detect the carbon dioxide concentration in the separated gas phase; and transmitting the detection result to a control unit 9. The control unit compares the result with a collection threshold and adjusts the system to either a first operating state or a second operating state. Specifically:

[0065] In one embodiment, when the carbon dioxide concentration in the separated gas phase is less than the collection threshold, the control unit 9 adjusts the system to a first operating state, allowing the separated gas phase to directly enter the gas collector 5. When the carbon dioxide concentration in the separated gas phase is greater than the collection threshold, the control unit 9 adjusts the system to a second operating state, allowing the separated gas phase to return to the photocatalytic reactor 2 to continue reacting until the carbon dioxide concentration in the separated gas phase is less than the collection threshold, at which point the separated gas phase enters the gas collector 5.

[0066] The collection threshold is 10-30% by volume, preferably 15-25% by volume, and more preferably 15-20% by volume.

[0067] In this embodiment, the control unit 9 flexibly controls the flow direction of the separated gas phase. On the one hand, it can make full use of the reactants in the hydrogenation reaction and improve the conversion rate of carbon dioxide. On the other hand, it can reduce the volume of the collected gas, reduce the volume of the gas collector 5 and the storage difficulty, thereby reducing equipment investment and saving costs.

[0068] In one embodiment, the system of this disclosure cycles 2 to 5 times when it is in the second working state, preferably 3 to 4 times.

[0069] In one embodiment, the obtained liquid product is fed into a fractionation device for separation, which can yield hydrocarbons with high purity. These hydrocarbons can be used directly as fuel or made into chemical reagents.

[0070] In one embodiment, the gaseous material collected by the gas collector 5 is fed into a hydrogen purification device for hydrogen purification treatment and then returned to the gas mixer for continued use.

[0071] In one embodiment, the liquid phase product obtained in liquid collector 4 mainly consists of hydrocarbons and water. The separated gas phase obtained in gas collector 5 mainly consists of hydrocarbons, hydrogen, and carbon dioxide. The hydrocarbons primarily include one or more of methane, ethylene, ethane, and propylene.

[0072] In one implementation, such as Figure 1 , Figure 2 and Figure 4 As shown, the methods for carrying out the catalytic reduction hydrogenation reaction of carbon dioxide include:

[0073] Carbon dioxide and hydrogen are mixed in gas mixer 1 to obtain hydrogenation reaction material; wherein the molar ratio of carbon dioxide to hydrogen is (2-4):1.

[0074] The hydrogenation reactants are fed into the feed chamber 25 of the photocatalytic reactor 2 and then enter the reaction chamber through the through-hole 27 at the top of the temperature regulating layer 21. Under light irradiation, they contact the catalyst on the arc-shaped catalyst plate 23 to undergo a hydrogenation reaction, yielding the hydrogenation reaction product. The hydrogenation reaction product is then discharged into the discharge chamber 26 through the through-hole 27 at the bottom of the temperature regulating layer 21. The conditions for the hydrogenation reaction include: a reaction temperature of 50–100°C, a reactant residence time of 5–10 s, and a light irradiation intensity of 20–200 W / m² for the tunable wavelength light source 24. 2 ;

[0075] A carbon dioxide concentration detector at the inlet of the photocatalytic reactor detects the carbon dioxide concentration in the hydrogenation reaction products and transmits the result to a control unit 9. The control unit compares the result with a first threshold and a second threshold: when the carbon dioxide concentration in the hydrogenation reaction material is less than the first threshold, the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction are increased; the first threshold is 28–33% by volume. When the carbon dioxide concentration in the hydrogenation reaction material is greater than the second threshold, the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction are decreased; the second threshold is 20–25% by volume.

[0076] The hydrogenation reaction products are introduced into a liquid collector 4 by the blower 3 for gas-liquid separation, resulting in a liquid product and a separated gas phase. The liquid product exits the system, and a carbon dioxide concentration detector detects the carbon dioxide concentration in the separated gas phase. The detection result is transmitted to a control unit 9, which compares the result with a collection threshold and adjusts the system to either a first or a second operating state. Specifically: when the carbon dioxide concentration in the separated gas phase is less than the collection threshold, the control unit 9 adjusts the system to the first operating state, allowing the separated gas phase to directly enter the gas collector 5. When the carbon dioxide concentration in the separated gas phase is greater than the collection threshold, the control unit 9 adjusts the system to the second operating state, allowing the separated gas phase to return to the photocatalytic reactor 2 for further reaction until the carbon dioxide concentration in the separated gas phase is less than the collection threshold, at which point the separated gas phase enters the gas collector 5. The collection threshold is 10–30% by volume.

[0077] The present disclosure is further illustrated by the following examples, but the present disclosure is not limited thereto. The hydrogen used in this disclosure is produced by electrolyzing water using electricity generated by a wind turbine, and has a purity of 98% by volume; the carbon dioxide used in this disclosure is obtained by burning fossil fuels, and has a purity of 98% by volume.

[0078] Example 1

[0079] use Figure 4 The system performs a carbon dioxide catalytic reduction and hydrogenation reaction, wherein the photocatalytic reactor used is such as... Figure 1 and Figure 2 As shown, the shell of the photocatalytic reactor has a cylindrical structure with a height of 1.2m and a cross-sectional diameter of 1m. The reaction chamber has a height of 0.8m and a cross-sectional diameter of 0.8m. The aperture of the through hole 27 is 5mm. The photocatalytic reactor uses an arc-shaped thin plate of catalyst, as shown in the figure. Figure 3 As shown, the arc α of the catalyst arc plate is 25 rad, the thickness is 1 mm, the height of the arc plate is 0.9 m, and the photocatalyst attached to the inner wall is titanium dioxide particles with a particle size of 30 nm.

[0080] Carbon dioxide and hydrogen are mixed in gas mixer 1 to obtain hydrogenation reaction material; wherein the molar ratio of hydrogen to carbon dioxide is 3:1.

[0081] The hydrogenation reactants are fed into the feed chamber 25 of the photocatalytic reactor 2 and enter the reaction chamber through the through-hole 27 on the top surface of the reaction chamber. Under light irradiation, they contact the catalyst on the arc-shaped catalyst plate 23 to carry out a hydrogenation reaction, yielding hydrogenation reaction products. The hydrogenation reaction products are then discharged into the discharge chamber 26 through the through-hole 27 on the bottom surface of the reaction chamber. The conditions for the hydrogenation reaction include: a reaction temperature of 70°C, a reactant residence time of 7 seconds, and a light irradiation intensity of 50 W / m² for the adjustable wavelength light source 24. 2 ;

[0082] A carbon dioxide concentration detector at the inlet of the photocatalytic reactor detects the carbon dioxide concentration in the hydrogenation reaction products and transmits the result to a control unit 9. The control unit compares the result with a first threshold and a second threshold: when the carbon dioxide concentration in the hydrogenation reaction material is less than the first threshold, the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction are increased; the first threshold is 30% by volume. When the carbon dioxide concentration in the hydrogenation reaction material is greater than the second threshold, the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction are decreased; the second threshold is 22% by volume.

[0083] The hydrogenation reaction products are introduced into a liquid collector 4 by the blower 3 for gas-liquid separation, resulting in a liquid product and a separated gas phase. The liquid product exits the system, and a carbon dioxide concentration detector detects the carbon dioxide concentration in the separated gas phase. The detection result is sent to a control unit 9, which compares the result with a collection threshold and adjusts the system to either a first or a second operating state. Specifically: when the carbon dioxide concentration in the separated gas phase is less than the collection threshold, the control unit 9 adjusts the system to the first operating state, allowing the separated gas phase to directly enter the gas collector 5. When the carbon dioxide concentration in the separated gas phase is greater than the collection threshold, the control unit 9 adjusts the system to the second operating state, allowing the separated gas phase to return to the photocatalytic reactor 2 for further reaction until the carbon dioxide concentration in the separated gas phase is less than the collection threshold, at which point the separated gas phase enters the gas collector 5. The collection threshold is 20% by volume.

[0084] Example 2

[0085] use Figure 4 The system performs a carbon dioxide catalytic reduction hydrogenation reaction, and the method for performing the carbon dioxide catalytic reduction hydrogenation reaction is the same as in Example 1, except that no carbon dioxide concentration detector is set at the inlet of the photocatalytic reactor of the system and no control unit is included, so that the reaction conditions of the photocatalytic reactor do not change with the concentration of carbon dioxide in the hydrogenation reaction material.

[0086] Example 3

[0087] use Figure 4 The system performs a carbon dioxide catalytic reduction hydrogenation reaction, and the method for performing the carbon dioxide catalytic reduction hydrogenation reaction is the same as in Example 1, except that the system does not have a circulating gas phase pipeline, so that the separated gas phase from the gas phase outlet of the liquid collector 4 is directly sent to the gas collector 5.

[0088] Comparative Example 1

[0089] use Figure 4 The system performs the catalytic reduction and hydrogenation reaction of carbon dioxide, the difference being that it uses... Figure 5The photocatalytic reactor in the reactor is used for hydrogenation. The reactor has a cylindrical structure and includes, from the outside to the inside, a heating layer 29, a reflective layer 30, a reaction tube 31, and a light source 32. The heating layer 29 is a hollow cylinder used to provide and maintain the required temperature for the entire reactor. The reflective layer 30 is attached to the inner wall of the heating layer 29 and is used to reflect the light emitted by the light source 32 multiple times. The light source 32 is rod-shaped and extends coaxially with the heating layer 29 to provide light radiation to perform the photocatalytic reaction. The reaction tube 31 is a hollow tube and extends spirally around the light source 32 through the entire heating layer. In addition, the two ends of the reaction tube 31 have a material inlet and a material outlet, respectively, and its inner wall is coated with a photocatalyst, thereby keeping the contents of the hollow tube spirally transported and reacting synchronously.

[0090] Table 1. Properties of the products in the examples and comparative examples.

[0091]

[0092]

[0093] As shown in Table 1, a comparison of the data from Examples 1-3 and Comparative Example 1 shows that the method of this disclosure can improve the hydrogenation reaction effect of carbon dioxide. Specifically, a comparison of the data from Examples 1 and 2 shows that flexibly adjusting the hydrogenation reaction conditions according to the carbon dioxide concentration of the hydrogenation reactant at the inlet of the photocatalytic reactor can further improve the hydrogenation reaction effect of carbon dioxide; a comparison of the data from Examples 1 and 3 shows that flexibly adjusting the flow of the separated gas phase to the gas collector or photocatalytic reactor according to the carbon dioxide concentration of the separated gas phase obtained from the liquid collector can further improve the hydrogenation reaction effect of carbon dioxide; a comparison of the data from Examples 1 and Comparative Example 1 shows that using the photocatalytic reactor of this disclosure can further improve the hydrogenation reaction effect of carbon dioxide.

[0094] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0095] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0096] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A system for catalytic reduction and hydrogenation of carbon dioxide using an arc-shaped thin-plate design, characterized in that, The system includes a gas mixer (1), a photocatalytic reactor (2), a fan (3), a liquid collector (4), and a gas collector (5). The photocatalytic reactor (2) includes a shell (20) with an overall cylindrical structure, a temperature regulating layer (21), a diffuse reflection layer (22), a catalyst arc-shaped thin plate assembly, and a tunable wavelength light source (24); the shell (20) is provided with a feed chamber (25), a reaction chamber, and a discharge chamber (26) from top to bottom; the temperature regulating layer (21) covers the outside of the reaction chamber; the diffuse reflection layer (22), the catalyst arc-shaped thin plate assembly, and the tunable wavelength light source (24) are arranged in sequence from the outside to the inside of the reaction chamber; The feeding chamber (25) and the discharging chamber (26) are respectively provided with a feeding port and a discharging port; the feeding port is connected to the outlet of the gas mixer (1), and the discharging port is connected to the inlet of the blower (3); the top and bottom surfaces of the reaction chamber are respectively provided with through holes (27) so that the feeding chamber (25) and the discharging chamber (26) are connected to the reaction chamber through the through holes (27); The catalyst arc-shaped thin plate assembly includes multiple catalyst arc-shaped thin plates (23), and the sidewalls of the catalyst arc-shaped thin plates (23) are attached with photocatalysts; the upper and lower ends of the catalyst arc-shaped thin plates (23) extend to the feed chamber (25) and the discharge chamber (26) respectively, and the concave surface of the arc-shaped thin plates faces the axis of the shell (20); The diffuse reflection layer (22) is disposed on the inner wall of the temperature regulating layer (21); The adjustable wavelength light source (24) is arranged along the axial direction of the housing (20) inside the reaction chamber and is coaxial with the reaction chamber; The adjustable wavelength light source (24) includes one or more of the following: xenon lamp light source, deuterium lamp light source, and halogen tungsten lamp light source; The surface of the catalyst arc-shaped thin plate (23) extends along the axial direction of the shell. The catalyst arc-shaped thin plate (23) is an arc-shaped thin plate of equal thickness and equal width at the top and bottom. The thickness of the arc-shaped thin plate is 1~10mm. Multiple catalyst arc-shaped thin plates (23) are arranged in parallel, and the multiple catalyst arc-shaped thin plates (23) are arranged at intervals along the same circumference on a plane perpendicular to the axial direction; The height ratio of the reaction chamber to the shell (20) is (0.5~0.7):1; The diameter of the through hole (27) is 5~10mm; The system also includes a control unit (9) and a carbon dioxide concentration detector located at the inlet of the photocatalytic reactor (2); The control unit is electrically connected to the carbon dioxide concentration detector, the tunable wavelength light source (24) and the temperature regulation layer (21), and is used to receive the carbon dioxide concentration signal from the carbon dioxide concentration detector and adjust the input power of the tunable wavelength light source (24) and / or the temperature regulation layer (21) according to the signal.

2. The system according to claim 1, characterized in that, The system also includes a gas phase outlet pipeline of the liquid collector (4) divided into a circulating gas phase pipeline and a gas phase collection pipeline; The gas phase outlet of the liquid collector (4) is connected to the feed inlet of the photocatalytic reactor (2) through the circulating gas phase pipeline; the gas phase outlet of the liquid collector (4) is connected to the inlet of the gas collector (5) through the gas phase collection pipeline.

3. A method for performing a carbon dioxide catalytic reduction hydrogenation reaction using the system described in claim 1 or 2, characterized in that, The method includes: Carbon dioxide and hydrogen are mixed in a gas mixer (1) to obtain hydrogenation reaction material; The hydrogenation reaction material is fed into the feed chamber (25) of the photocatalytic reactor (2) and enters the reaction chamber through the through hole (27) on the top surface of the reaction chamber. Under light irradiation, it contacts the catalyst on the catalyst arc-shaped thin plate (23) to carry out the hydrogenation reaction and obtain the hydrogenation reaction product. The hydrogenation reaction product is then fed into the discharge chamber (26) through the through hole (27) on the bottom surface of the reaction chamber. The hydrogenation reaction products in the discharge chamber (26) are sequentially passed through the blower (3) and the liquid collector (4) into the gas collector (5).

4. The method according to claim 3, characterized in that, The method further includes increasing the reaction temperature and / or the light irradiation intensity of the hydrogenation reaction when the carbon dioxide concentration in the hydrogenation reactants is less than a first threshold; the first threshold is 28-33% by volume. When the carbon dioxide concentration in the hydrogenation reaction material is greater than the second threshold, the reaction temperature of the hydrogenation reaction and / or the light irradiation intensity of the hydrogenation reaction are reduced; the second threshold is 20-25% by volume.

5. The method according to claim 3, characterized in that, The method also includes causing the hydrogenation reaction product to enter the liquid collector (4) under the action of the blower (3) for gas-liquid separation to obtain liquid phase product and separated gas phase; When the carbon dioxide concentration in the separated gas phase is less than the collection threshold, the separated gas phase is allowed to enter the gas collector (5). When the carbon dioxide concentration in the separated gas phase is greater than the collection threshold, the separated gas phase is returned to the photocatalytic reactor (2) to continue the reaction until the carbon dioxide content in the separated gas phase is less than the collection threshold, at which point the separated gas phase enters the gas collector (5). The collection threshold is 10-30 units of volume.

6. The method according to claim 3, characterized in that, Photocatalysts include one or more of titanium dioxide, zinc oxide, or tin oxide; The conditions for the hydrogenation reaction include: a reaction temperature of 50~100℃, a reactant residence time of 5~10s, and a light irradiance of 20~200W / m² from the tunable wavelength light source (24). 2 .

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